Method and apparatus for making a filter element

ABSTRACT

There is disclosed a method for making a filter element comprising the steps of: advancing two or more sheets of filtering material in a longitudinal direction; separating the two or more sheets of longitudinally advancing filtering material; gathering the separated sheets of longitudinally advancing filtering material to form a partially gathered rod of filtering material having a longitudinally extending recess; inserting an additive release vessel into the longitudinally extending recess; gathering the filtering material around the additive release vessel to close the recess and thereby form a rod comprising a longitudinally extending core of filtering material and one or more additive release vessels.

The present invention relates filter elements and filters, methods formaking filter elements, and an apparatus for making filter elements.

Tobacco filter elements or filters which include a frangible capsule areknown in the art. The frangible capsule typically contains a liquidadditive which may modify the properties of the tobacco smoke whichpasses through the filter or filter element. For example, the capsulemay contain a flavourant such as menthol that modifies the flavour andother sensory properties of the tobacco smoke. Typically, the capsule isbroken by the user prior to smoking such that the contents of thecapsule is released into the surrounding filtering material.

Tobacco filter elements or filters typically include a core comprisingcellulose acetate filtering material. Cellulose acetate filteringmaterial can be slow to degrade under normal environmental conditions.Filtering material made from paper or other non-woven materials can haveimproved degradability and other properties.

Methods for making a filter element containing a capsule in which thefilter element is formed from cellulose acetate tow are known in theart. Inserting a capsule into a filter element formed from sheetfiltering material such as paper or a nonwoven material is morechallenging, and problems relating to capsule placement and filteringmaterial homogeneity are common.

There is a need for new methods and apparatus for making filter elementsincluding capsules and that are formed from sheet filtering materialsuch as paper or non-woven materials. There is also a need for newfilters or filter elements which include capsules and are formed fromsheet filtering material such as paper or non-woven materials.

In a first aspect of the present invention there is provided a methodfor making a filter element comprising the steps of: advancing two ormore sheets of filtering material in a longitudinal direction;separating the two or more sheets of longitudinally advancing filteringmaterial; gathering the separated sheets of longitudinally advancingfiltering material to form a partially gathered rod of filteringmaterial having a longitudinally extending recess; inserting an additiverelease vessel into the longitudinally extending recess; gathering thefiltering material around the additive release vessel to close therecess and thereby forming a rod comprising a longitudinally extendingcore of filtering material and one or more additive release vessels.

The applicant has found that using two or more sheets of filteringmaterial and separating the two or more sheets before these are gatheredleads to a partially gathered rod of filtering material which has alongitudinally extending recess, into which one or more capsules can beinserted. The formation of the recess leads to improved capsulepositioning in filter elements made from sheet filtering material, suchas paper or a non-woven material. The applicant has also found that theprocess of the invention leads to a filter element formed from sheetfiltering material having improved homogeneity.

The two or more sheets of filtering material advancing longitudinallymay be continuously advancing longitudinally.

The two or more sheets of longitudinally advancing filtering materialmay be separated such that there is a gap between the two or more sheetsof longitudinally advancing filtering material, and the size of the gapmay reduce as the two or more sheets are partially gathered. Prior tocapsule insertion, the two or more sheets of filtering material are notcompletely gathered, and the size of the gap between the two sheetsreduces to form a recess in the rod of partially gathered filteringmaterial. As the two or more sheets are gathered, the two or more sheetsmay remain substantially vertically aligned. Herein vertically alignedmeans aligned in the plane perpendicular to the plane in which thesheets of filtering material longitudinally advance and perpendicular tothe plane that is transverse to plane in which the sheets of filteringmaterial longitudinally advance.

Preferably, the two or more sheets of longitudinally advancing filteringmaterial are separated by a separator. Preferably, the step of gatheringthe separated two or more sheets of longitudinally advancing filteringmaterial comprises drawing the separated two or more sheets oflongitudinally advancing filtering material into a gathering chamber.

The applicant has found that the separator keeps the folds of the sheetmaterial apart such that the capsule can be placed into the centre ofthe partially gathered filtering material, so leading to improvedcapsule positioning.

Preferably, the gathering chamber is a hollow element configured togather or condense filtering material.

Preferably, the separator is coupled to the gathering chamber such thatthe two or more sheets of longitudinally advancing filtering materialare separated before entering the gathering chamber, and the separatorprevents complete gathering of the two or more sheets of longitudinallyadvancing filtering material to thereby form a longitudinally extendingrecess in the partially gathered filtering material.

The gathering chamber may comprise an inlet for receiving the separatedsheets of filtering material and an outlet for the gathered or partiallygathered filtering material to exit. Preferably, the gathering chamberis tapered longitudinally from the inlet, such that the inlet has alarger internal diameter than the outlet. The gathering chamber acts togather (for example condense) the two or more sheets of filteringmaterial into a partially gathered rod of filtering material having alongitudinally extending recess. The gathering chamber may comprise anaperture for receiving an inserter for inserting one or more additiverelease vessels into the longitudinally extending recess. The aperturemay be positioned between the inlet and the outlet.

Following insertion of the or each additive release vessel, thegathering chamber may further gather the partially gathered filteringmaterial around the additive release vessel to close the recess andthereby form a rod comprising a longitudinally extending core offiltering material and one or more additive release vessels. Thegathering chamber may be tapered after or from the aperture to therebyfurther gather the partially gathered filtering material. The furthergathering may alternatively be performed by a further gathering chamberjoined to the first gathering chamber.

A further step of applying an outer wrapper may help to complete thegathering of the partially gathered rod of filtering material andcomplete the closing of the longitudinally extending recess.

Preferably, the separator is longitudinally tapered. The separator mayhave a first end having a first diameter, and a second end having asecond diameter, wherein the second diameter is smaller than the firstdiameter. The separator may extend into and along at least part of thelength of the gathering chamber. The first end of the separator mayprotrude from the gathering chamber and the second end of the separatormay be positioned inside the gathering chamber. The separator may betapered in the same direction as the gathering chamber. The separatormay be substantially conical or frustroconical. The tapered shape of theseparator separates the two or more sheets of filtering material whilealso facilitating the partial gathering of the sheets of filteringmaterial.

The gathering chamber may be tapered in the same direction as theseparator so thereby partially gathering the two or more sheets offiltering material. The applicant has found that even at the point atwhich the separator is narrowest, the two or more sheets of filteringmaterial remain separated, and after the sheets of filtering materialadvance beyond the separator, a recess remains in the partially gatheredrod, and the recess can receive the or each additive release vessels.

The applicant has found that the configuration of the separator and thegathering chamber maintains alignment of the two or more sheets offiltering material. For example, vertical alignment of the two or moresheets of filtering material is maintained. Herein vertical alignmentmeans alignment in the plane perpendicular to the plane in which thesheets of filtering material longitudinally advance and perpendicular tothe plane that is transverse to plane in which the sheets of filteringmaterial longitudinally advance. The applicant has found thatmaintaining the alignment of the two or more sheets of filteringmaterial whilst the filtering material is gathered leads to a core offiltering material having improved homogeneity and assists with capsuleplacement.

In one embodiment, the separated two or more longitudinally advancingsheets of filtering material may be drawn into a preliminary chamberbefore entering the gathering chamber. The preliminary chamber maycomprise an inlet and an outlet. The preliminary chamber may be taperedlongitudinally away from the inlet. The inlet may have a larger internaldiameter than the outlet. The outlet of the preliminary chamber may bejoined to the inlet of the gathering chamber, and the separator mayextend into and along at least part of the length of the preliminarychamber. The first end of the separator may protrude from thepreliminary chamber and the second end of the separator may bepositioned inside the preliminary chamber. The preliminary chamber andthe separator may be configured such that the two or more sheets oflongitudinally advancing filtering material are separated beforeentering the preliminary chamber, and the separator prevents completegathering of the two or more sheets of longitudinally advancingfiltering material to thereby form a longitudinally extending recess inthe partially gathered filtering material.

The applicant has found that the presence of a preliminary chamber helpsto partially gather the filtering material before it enters thegathering chamber. In the case of the method of the invention utilisinga preliminary chamber, the gathering chamber comprises an inlet joinedto the outlet of the preliminary chamber and, the gathering chambercomprises an aperture for receiving the inserter. The gathering chambermay taper longitudinally from or after the aperture to thereby gatherthe two or more sheets of filtering material around the additive releasevessel to close the recess and thereby form a continuous rod comprisinga longitudinally extending core of filtering material and one or moreadditive release vessels.

The additive release vessel inserter may comprise a rotating drum orwheel that rotates to thereby insert an additive release vessel into therecess at regular intervals.

The method may comprise a step of cutting the rod to form a filterelement comprising a longitudinally extending core of filtering materialand one or more additive release vessels.

The method may comprise a step of advancing a sheet of filteringmaterial in the longitudinal direction; and cutting the sheetlongitudinally to thereby form two or more sheets of longitudinallyextending filtering material. The two or more sheets of filteringmaterial continue to advance longitudinally following the cutting. Thesheet of longitudinally advancing filtering material may be cut to formtwo, three four or more sheets of longitudinally extending filteringmaterial. Alternatively, the filtering material may be cut by a separateprocess and wound on to a reel for use in the methods of the invention.

The two or more sheets of filtering material may be embossed. Forexample, the method may comprise a step of embossing the two or moresheets of longitudinally extending filtering material. The embossingimparts an embossed profile onto the two or more sheets of filteringmaterial. The embossing may be carried out by an embosser. The embossermay comprise a rotating drum (for example an embossing roller)comprising projections (e.g. spikes) extending away from the surface ofthe drum (for example the surface of the embossing roller). Theapplicant has found that the step of embossing the two or more sheetsleads to a filter element having a desired pressure drop and a compactor dense end visual appearance.

The two or more sheets of filtering material may comprise 2, 3 or 4sheets of filtering material.

The two or more sheets of filtering material may each have a width of 50to 200 mm, for example 75 to 175 mm, for example 80 to 150 mm, forexample 90 to 125 mm, for example 100 to 120 mm, for example 110 mm.

The two or more sheets of filtering material may have a thickness offrom 50 μm to 100 μm, for example 60 μm to 90 μm, for example, 70 μm to90 μm, for example 80 μm to 90 μm, for example 82 μm to 88 μm, forexample 83 μm to 87 μm, for example 84 μm to 86 μm, for example 85 μm.

The filtering material may be tobacco filtering material. The filteringmaterial may comprise paper or a non-woven material such as an air laidnon-woven materials such as McAirlaid material, a melt-spun non-wovenmaterial, and/or a melt-blown non-woven material.

Preferably, the filtering material comprises or is paper.

The paper may have a basis weight of from 25 g/m² to 65 g/m², forexample 30 to 60 g/m², for example 30 to 50 g/m², for example 30 to 40g/m², for example 32 to 38 g/m², for example 33 to 37 g/m², for example36 g/m².

Preferably, the additive release vessel may be a capsule, for example afrangible capsule. The additive release vessel, such as a capsule, suchas a frangible capsule, may comprise an additive. The additive maycomprise a smoke modifying agent such as a flavourant and/or a liquid,solid or other material e.g. to aid smoke filtration. The flavourantmay, for example, be menthol, spearmint, peppermint, nutmeg, cinnamon,clove, lemon, chocolate, peach, strawberry, vanilla or the like.

The method may comprise a step of wrapping the continuous rod comprisinga longitudinally extending core of filtering material and one or moreadditive release vessels before the continuous rod is cut. The step ofwrapping may comprise applying an outer wrapper, for example a plugwrap, which surrounds the continuous rod.

The method may comprise a step of applying an additive material to thetwo or more sheets of filtering material. The additive may be appliedfollowing the step of embossing. The additive may be a taste modifyingagent and/or a flavourant. The flavourant may, for example, be menthol,spearmint, peppermint, nutmeg, cinnamon, clove, lemon, chocolate, peach,strawberry, vanilla or the like.

In a further aspect of the present invention, there is provided a filterelement obtained according to the method of the present invention, forexample according to the method of any statement set out above.

In a further aspect of the present invention, there is provided a filterelement comprising a longitudinally extending core of filtering materialand an additive release vessel within the longitudinally extending coreof filtering material; wherein the longitudinally extending core offiltering material is formed from two or more sheets of filteringmaterial.

The additive release vessel may be a capsule such as a frangiblecapsule. The additive release vessel, such as a capsule, such as afrangible capsule, may comprise an additive. The additive may comprise asmoke modifying agent such as a flavourant and/or a liquid, solid orother material e.g. to aid smoke filtration. The flavourant may, forexample, be menthol, spearmint, peppermint, nutmeg, cinnamon, clove,lemon, chocolate, peach, strawberry, vanilla or the like. The amount ofadditive, for example flavourant, may be less than 35 mg per filterelement.

The additive release vessel, such as a capsule or frangible capsule, maybe spherical. The additive release vessel (such as a capsule orfrangible capsule) may have a width at its broadest point of 2.0 to 4mm, for example 2.8 to 3.5 mm.

The filter element may be formed from 2, 3, 4 or more sheets offiltering material.

The two or more sheets of filtering material may each have a width of 50to 200 mm, for example 75 to 175 mm, for example 80 to 150 mm, forexample 90 to 125 mm, for example 100 to 120 mm, for example 110 mm.

The two or more sheets of filtering material may have a thickness offrom 50 μm to 100 μm, for example 60 μm to 90 μm, for example, 70 μm to90 μm, for example 80 μm to 90 μm, for example 82 μm to 88 μm, forexample 83 μm to 87 μm, for example 84 μm to 86 μm, for example 85 μm.

The filtering material may comprise a paper or non-woven material. Thenon-woven material may be an air laid non-woven material, such asMcAirlaid material, a melt-spun non-woven material, and/or a melt-blownnon-woven material.

The paper may have a basis weight of from 25 g/m² to 65 g/m², forexample 30 to 60 g/m², for example 30 to 50 g/m², for example 30 to 40g/m², for example 32 to 38 g/m², for example 33 to 37 g/m², for example36 g/m².

The two or more sheets of filtering material may be embossed.

The outer circumference of the filter element may be between 14 and 26mm, for example between 16 and 26 mm.

The length of the filter element may be between 4.0 mm and 50 mm, forexample between and 32 mm. The filter element may be for use as part ofa tobacco smoke filter or filter for a non-tobacco smokable material,for example marijuana. The filter element of the present invention maybe incorporated into a multi-segment filter as a single segment. Thiswould allow for an increase in the number of features that could beincorporated into the filter. For example, a filter element according toany statement set out above may be joined with a further filter element.

The filter element of the present invention may be incorporated into asmoking article, such as a cigarette, cigarillo, cigar and the like. Thefilter element of the present invention may be incorporated into atobacco heating product or an e-cigarette. The filter element may alsobe used alone or as part of a filter which is assembled by a user toform a smoking article, for example a roll-your-own smoking article.

In a further aspect of the present invention, there is provided afilter, for example a tobacco smoke filter, comprising a filter elementaccording to any statement set out above. The filter, for example atobacco smoke filter, may further comprise one or more further filterelement(s). Such a filter which comprises more than one filter elementmay be referred to as a multi segment filter.

The filter may comprise an outer wrapper, for example plugwrap, whichsurrounds the filter element or one or more filter elements. The wrappermay be paper, for example an air permeable paper. The wrapper may have abasis weight from 20 to 100 grams per square metre, for example from 20to 50 grams per square metre. The wrapper may be coated. The furtherfilter element may be wrapped by an outer wrapper, for example aplugwrap, which surrounds the further filter element. The filter elementas defined according to any statement set out above and a further filterelement may together be wrapped by an outer wrapper, such as a plugwrap. The outer wrapper may function to join the filter elements andsecure them in place.

In a further aspect of the present invention there is provided a smokingarticle comprising a filter or filter element as described above. Thesmoking article may include a filter as set out above that is joined toa wrapped rod of smoking material such as tobacco smoking material. Thesmoking article may further comprise a tipping wrapper, for example atipping paper. The tipping wrapper joins the wrapped rod of smokingmaterial to the filter by engaging around the adjacent ends of thefilter and the wrapped rod of smoking material. The tipping wrapper maybe configured to leave some of the outer surface of the filter or filterwrapper exposed. Alternatively, the filter may be joined to the wrappedrod of smoking material by a full tipping wrapper which engages aroundthe full filter or mouthpiece length and the adjacent end of the rod ofsmoking material.

The filter element, filter or smoking article according to the inventionmay be unventilated, or may be ventilated by methods well known in theart, e.g. by use of a pre-perforated or air-permeable filter wrapper(plugwrap) or tipping wrapper (tipping paper), and/or laser perforationof the filter wrapper and/or tipping wrapper. The mouthpiece, filter,filter element or smoking article according to the invention may beventilated by laser perforation of the longitudinally extending core offiltering material (as well as wrapper(s) (plugwrap) and tipping wrapper(tipping paper) if present). A ventilating full tipping wrapper (tippingpaper) may likewise be inherently air-permeable or may be provided withventilation holes, and for ventilated products where both filter wrapper(plugwrap) and tipping wrapper (tipping paper) are present, ventilationthrough the tipping wrapper (tipping paper) will usually be in registerwith that through the filter wrapper (plug wrap). Ventilation holesthrough a filter wrapper (plugwrap), or through a tipping wrapper(tipping paper), or through both simultaneously, may be made by laserperforation during mouthpiece, filter or filter element production.

In a further aspect of the present invention there is provided amultiple rod comprising a plurality of filter elements according to theinvention arranged end-to-end in a mirror image relationship.

In a further aspect of the present invention, there is provided anapparatus for making a filter element comprising: a separator forseparating two or more longitudinally advancing sheets of filteringmaterial; a gathering chamber configured to gather the separatedlongitudinally advancing sheets of filtering material and form a rod ofpartially gathered filtering material; wherein the separator is coupledto the gathering chamber, such that the separator and the gatheringchamber are configured to form a longitudinally extending recess in therod of partially gathered filtering material; and an inserter configuredto insert one or more additive release vessels into the longitudinallyextending recess.

Preferably the gathering chamber is a hollow section configured togather or condense filtering material to form a longitudinally extendingrod of filtering material.

Preferably, the separator and gathering chamber are coupled such thatthe two or more sheets of longitudinally advancing filtering materialare separated before entering the gathering chamber, and the separatorprevents complete gathering of the two or more sheets of longitudinallyadvancing filtering material to thereby form a longitudinally extendingrecess in the partially gathered filtering material.

The gathering chamber may comprise an inlet for receiving the separatedsheets of filtering material and an outlet for the gathered or partiallygathered filtering material to exit. Preferably, the gathering chamberis tapered longitudinally away from the inlet, such that the inlet has alarger internal diameter than the outlet. The gathering chamber acts togather (for example condense) the two or more sheets of filteringmaterial into a partially gathered rod of filtering material having alongitudinally extending recess.

Preferably, the separator may be longitudinally tapered. The separatormay have a first end having a first diameter, and a second end having asecond diameter, wherein the second diameter is smaller than the firstdiameter. The separator may extend into and along at least part of thelength of the gathering chamber. The first end of the separator mayprotrude from the gathering chamber and the second end of the separatormay be positioned inside the gathering chamber. The separator may betapered in the same direction as the gathering chamber.

The separator may be substantially conical or frustroconical. Thetapered shape of the separator is configured to separate the two or moresheets of filtering material while also facilitating the partialgathering of the sheets of filtering material. The gathering chamber maybe tapered in the same direction as the separator so thereby partiallygathering the two or more sheets of filtering material. The applicanthas found that even at the point at which the separator is narrowest,the two or more sheets of filtering material remain separated, and afterthe sheets of filtering material advance beyond the separator, a recessremains in the partially gathered rod, and the recess can receive the oreach additive release vessels.

The applicant has found that the configuration of the separator and thegathering chamber maintains alignment of the two or more sheets offiltering material. For example, vertical alignment of the two or moresheets of filtering material is maintained. Herein vertical alignmentmeans alignment in the plane perpendicular to the plane in which thesheets of filtering material longitudinally advance and perpendicular tothe plane that is transverse to plane in which the sheets of filteringmaterial longitudinally advance. The applicant has found thatmaintaining the alignment of the two or more sheets of filteringmaterial whilst the filtering material is gathered leads to a core offiltering material having improved homogeneity and also assists withcapsule placement. The applicant has found that the separator keeps thefolds of the sheet material apart such that the capsule can be placedinto the centre of the partially gathered filtering material, so leadingto improved capsule positioning.

The gathering chamber may comprise an aperture, for example alongitudinally extending aperture, for receiving the inserter. Thisconfiguration enables the inserter to insert one or more additiverelease vessels into the recess formed in the partially gathered rod offiltering material. The gathering chamber may be tapered from or afterthe aperture to facilitate further gathering of the partially gatheredrod of filtering material around the additive release vessel to closethe recess and thereby form a continuous rod comprising a longitudinallyextending core of filtering material and one or more additive releasevessels.

The separator may extend into and along at least part of the length ofthe gathering chamber, but the separator does not extend as far as thelongitudinally extending aperture. This configuration allows for the oneor more additive release vessels to be inserted into the recess.

In an embodiment, the apparatus may comprise a preliminary chambercomprising: an inlet and an outlet; wherein the preliminary chamber istapered longitudinally away from the inlet. The inlet may have a largerinternal diameter than the outlet.

The separator may be longitudinally tapered and extends into and alongat least part of the length of the preliminary chamber. The first end ofthe separator may protrude from the preliminary chamber and the secondend of the separator may be positioned inside the preliminary chamber.The separator may be tapered in the same direction as the preliminarychamber. The separator being tapered in the same direction as thepreliminary chamber means that the separator is able to be positionedpartially inside of the preliminary chamber.

The applicant has found that the preliminary chamber helps to partiallygather the filtering material before it enters the gathering chamber.

In this embodiment, the gathering chamber comprises an inlet joined tothe outlet of the preliminary chamber, and the gathering chambercomprises an aperture for receiving the inserter. The gathering chambermay taper longitudinally from the end of the aperture to thereby gatherthe two or more sheets of filtering material around the additive releasevessel to close the recess and thereby form a continuous rod comprisinga longitudinally extending core of filtering material and one or moreadditive release vessels.

The apparatus may comprise a cutter configured to cut a single sheet offiltering material into two or more longitudinally extending sheets offiltering material. The cutter may be configured to cut the single sheetof filtering material into two, three, four or more longitudinallyextending sheets of filtering material.

The inserter may comprise a rotating drum or wheel configured to insertthe or each additive release vessel into the longitudinally extendingrecess.

The apparatus may comprise a rod cutter configured to cut a rodcomprising a longitudinally extending core of filtering material and oneor more additive release vessels to form a filter element.

The apparatus may comprise an embosser. The embosser may comprise arotating drum (for example an embossing roller) comprising projections(e.g. spikes) extending away from the surface of the drum (for examplethe surface of the embossing roller). The embosser may emboss the two ormore sheets of filtering material. The applicant has found thatembossing the two or more sheets leads to a filter element having adesired pressure drop and a compact or dense end visual appearance.

The apparatus may comprise a wrapping element for wrapping the advancingrod before it is cut.

The apparatus may comprise an additive applicator for applying anadditive to the two or more sheets of filtering material. The additivemay be a taste modifying agent and/or a flavourant. The flavourant may,for example, be menthol, spearmint, peppermint, nutmeg, cinnamon, clove,lemon, chocolate, peach, strawberry, vanilla or the like.

In a further aspect of the invention, there is provided an apparatus forseparating and gathering two or more sheets of filtering material, theapparatus comprising: a gathering chamber comprising an inlet and anoutlet, wherein the inlet has a larger diameter than the outlet suchthat the gathering chamber is longitudinally tapered; a separatorextending at least part of the way into the gathering chamber andprotruding from the inlet of the gathering chamber; wherein theseparator and the gathering chamber are configured to separate andpartially gather two or more sheets of filtering material to therebyform a partially gathered longitudinally extending rod of filteringmaterial comprising a longitudinally extending recess.

The gathering chamber may comprise an inlet for receiving the separatedsheets of filtering material and an outlet for the partially gatheredfiltering material to exit. The gathering chamber acts to gather (forexample condense) the two or more sheets of filtering material into apartially gathered rod of filtering material having a longitudinallyextending recess.

The separator may be tapered in the same direction as the gatheringchamber.

The separator may be substantially conical or frustroconical. Thetapered shape of the separator separates the two or more sheets offiltering material while also facilitating the partial gathering of thesheets of filtering material. The gathering chamber may be tapered inthe same direction as the separator so thereby partially gathering thetwo or more sheets of filtering material. The applicant has found thateven at the point at which the separator is narrowest, the two or moresheets of filtering material remain separated, and after the sheets offiltering material advance beyond the separator, a recess remains in thepartially gathered rod, and the recess can receive the or each additiverelease vessel.

The applicant has found that the configuration of the separator and thegathering chamber maintains alignment of the two or more sheets offiltering material. For example, vertical alignment of the two or moresheets of filtering material is maintained. Herein vertical alignmentmeans alignment in the plane perpendicular to the plane in which thesheets of filtering material longitudinally advance and perpendicular tothe plane that is transverse to plane in which the sheets of filteringmaterial longitudinally advance. The applicant has found thatmaintaining the alignment of the two or more sheets of filteringmaterial whilst the filtering material is gathered leads to a core offiltering material having improved homogeneity and also assists withcapsule placement. The applicant has found that the separator keeps thefolds of the sheet material apart such that the capsule can be placedinto the centre of the partially gathered filtering material, so leadingto improved capsule positioning.

The gathering chamber may comprise an aperture, for example alongitudinally extending aperture, for receiving an inserter forinserting one or more additive release vessels. This configurationenables the inserter to insert one or more additive release vessels intothe recess formed in the partially gathered rod of filtering material.The gathering chamber may be tapered from or after the aperture tofacilitate further gathering of the partially gathered rod of filteringmaterial around the additive release vessel to close the recess andthereby form a continuous rod comprising a longitudinally extending coreof filtering material and one or more additive release vessels.

The separator may extend into and along at least part of the length ofthe gathering chamber, but the separator does not extend as far as thelongitudinally extending aperture. This configuration allows for the oneor more additive release vessels to be inserted into the recess.

In an embodiment, the apparatus may comprise a preliminary chambercomprising: an inlet and an outlet; wherein the preliminary chamber istapered longitudinally away from the inlet. The inlet may have a largerinternal diameter than the outlet.

The separator may be longitudinally tapered and extends into and alongat least part of the length of the preliminary chamber. The first end ofthe separator may protrude from the preliminary chamber and the secondend of the separator may be positioned inside the preliminary chamber.The separator may be tapered in the same direction as the preliminarychamber. The separator being tapered in the same direction as thepreliminary chamber means that the separator is able to be positionedpartially inside of the preliminary chamber.

The applicant has found that the preliminary chamber helps to partiallygather the filtering material before it enters the gathering chamber.

In this embodiment, the gathering chamber comprises an inlet joined tothe outlet of the preliminary chamber, and the gathering chambercomprises an aperture for receiving the inserter. The gathering chambermay taper longitudinally from or after the end of the aperture tothereby gather the two or more sheets of filtering material around theadditive release vessel to close the recess and thereby form acontinuous rod comprising a longitudinally extending core of filteringmaterial and one or more additive release vessels.

The apparatus for separating and gathering two or more sheets offiltering material may be included as part of an apparatus for making afilter element.

The gathering chamber may also be referred to as a gathering shoe. Thepreliminary chamber may also be referred to as a supporting shoe.

Preferred embodiments of the invention will now be described byreference to the accompanying drawings in which:

FIG. 1 is a schematic overview of the method of the present invention;

FIG. 2 is a perspective view of part of the apparatus according to thepresent invention;

FIG. 3 is a side view of part of the apparatus according to the presentinvention in use;

FIG. 4 is a rear view of part of the apparatus according to the presentinvention in use;

FIG. 5 is a side view of the separator according to the presentinvention;

FIG. 6 is a perspective view of a filter element according to thepresent invention

FIG. 7 is a sectional view of a filter element according to the presentinvention.

FIG. 8 is a perspective view of an apparatus for separating andgathering two or more sheets of filtering material.

FIG. 1 shows a schematic overview of the process of the presentinvention.

Filtering material 104 is unwound from a reel 102 and advanced in alongitudinal direction L. The filtering material is a pre-cut sheet ofpaper filtering material comprising two individual sheets of paperfiltering material wound onto the same reel 102. Each sheet has a widthof 110 mm, a thickness of 85 μm and a basis weight of 36 g/m². The twosheets 104 advance together longitudinally in parallel. The longitudinaledge of one sheet abuts the longitudinal edge of the other sheet. Itwill be appreciated that more than two sheets of filtering materialcould be used, for example 3 or 4 or more sheets of longitudinallyadvancing filtering material. It will be appreciated that the two ormore sheets of filtering material may be formed as part of the method ofthe invention. For example, a single sheet of filtering material couldbe advanced longitudinally and cut longitudinally into multiple sheets.It will be appreciated that a non-woven sheet material could also beused.

The advancing sheets of filtering material 104 are embossed by anembosser 106. The embosser 106 comprises a rotating roller comprisingspikes which protrude from the outer surface of the roller. Theadvancing sheets of filtering material are drawn between the roller anda flat surface or between the roller and a second smooth roller (asshown in FIG. 1 ) and the embossing roller embosses the sheets offiltering material. The applicant has found that embossing the sheets offiltering material leads to a desired pressure drop and leads to a denseor compact visual end appearance.

The embossed sheets of filtering material are then advanced andflattened by a wire 108. The flattened sheets of filtering material arethen separated by a separator in the form of a separator cone 110. Theseparated sheets of filtering material pass into a preliminary chamber116, and the sheets remain separated as the two sheets are gatheredtogether such that a recess is formed in the partially gathered rod offiltering material. The partially gathered rod of filtering materialthen passes into the gathering chamber 122 and one or more capsules areinserted into the recess in the partially gathered rod of filteringmaterial by means of a capsule inserter 130 comprising a rotating wheel.The rod is then further gathered and condensed by the gathering chamber122 to thereby close the recess and form a rod comprising alongitudinally extending core of filtering material and one or moreadditive release vessel within the core of filtering material.

The rod is advanced in the longitudinal direction and is wrapped with anouter wrapper, such as a plug wrap to form a wrapped rod. The rod iswrapped with an outer wrapper using techniques known in the art. Finallythe wrapped rod is cut by a rod cutter 140 to form a filter elementcomprising a longitudinally extending core of filtering materialcomprising one or more additive release vessels located within the coreof filtering material. The rod cutter is a standard rod cutter known inthe art.

The gathering and capsule insertion steps and apparatus will now bedescribed in more detail with reference to FIGS. 2 to 4 and 8 .

The flattened tow 104 is advanced and before it enters the preliminarychamber 116 the two sheets are separated by the cone 110. The cone 110comprises a first end 112 and a second end 114. The first end has awider diameter than the second end such that the cone taperslongitudinally from the first end to the second end. The cone is formedfrom a metal.

As shown in FIGS. 3 and 4 , the cone 110 separates the two sheets offiltering material as these enter the preliminary chamber 116.

The preliminary chamber 116 comprises an inlet 118 and an outlet 120.The inlet 118 has a larger diameter than the outlet 120 such that thepreliminary chamber 116 tapers longitudinally from the inlet 118 to theoutlet 120. The cone 110 is positioned partially within the preliminarychamber 116 such that part of the cone 110 protrudes out of and awayfrom the inlet 118 of the preliminary chamber 116. The preliminarychamber 116 is formed from a metal.

The cone 110 is fixed within the preliminary chamber 116 by a mechanicalsupport. Before the sheets of filtering material are drawn into thepreliminary chamber 116, the sheets are separated by the cone 110. Asthe sheets of filtering material are drawn into the preliminary chamber116, the sheets remain separated by the cone 110, but as the filteringmaterial advances longitudinally, the gap between the sheets reduces asthe diameter of the cone 110 reduces. At the same time, the filteringmaterial is partially gathered by the inner surfaces of the preliminarychamber 116. As the diameter of the preliminary chamber 116 decreases,the filtering material is gathered and condensed to form a partiallygathered rod of filtering material. The cone 110 prevents completegathering of the filtering material and leads to the formation of arecess in the partially gathered rod off filtering material. Theapplicant has found that the cone 110 keeps the folds of the sheetmaterial apart such that the capsule can be placed into the centre ofthe partially gathered filtering material, so leading to improvedcapsule positioning.

The partially gathered rod of filtering material is drawn into thegathering chamber in the form of gathering shoe 122. Gathering shoe 122comprises an inlet 124 and an outlet (not shown. The inlet of thegathering shoe has a larger diameter than the outlet of the gatheringshoe. The cross sectional diameter of the gathering shoe initiallyremains constant in a first section 126. In a second section 127 of thegathering shoe, the cross sectional diameter decreases such that thesecond section 127 is longitudinally tapered. A third section 128 has aconstant cross sectional diameter. It will be appreciated that thegathering shoe may not include a third section 128. Positioned in a topsurface of the gathering shoe is a longitudinally extending aperturewhich extends partially along the first section 126 and second section127 of the gathering shoe. The aperture is configured to receive thecapsule inserter wheel 130.

The capsule inserter wheel 130 is fed by a hopper (not shown).

The capsule inserter wheel is one known in the art. The capsule inserterwheel utilises a vacuum and air jet system to collect and insert thecapsules into the longitudinally extending recess. In such a system, afirst wheel (not shown) comprises a plurality of grooves spacedequidistantly around its cylindrical surface. A hopper, which containsthe capsules, releases the capsules and the capsules are collected bythe grooves in the first wheel. A vacuum pump applies suction to thegrooves such that each groove collects a single capsule.

A second smaller wheel 130 is positioned beneath the first wheel. Thesecond wheel 130 comprises a plurality of grooves spaced equidistantlyaround its cylindrical surface. The capsules collected by the firstwheel are transferred to the second wheel 130. At the bottom of thetravel path of a given groove on the first wheel, the suction applied tothat groove stops, and the capsule is transferred by gravity to acorresponding groove on the second wheel. The capsules are retained inthe grooves of the second wheel 130 by suction applied by a vacuum pump.The bottom part of the second wheel 130 is positioned within theaperture of the gathering shoe 122. At the bottom of the travel path ofa given groove, the suction applied to that particular groove is stoppedand is replaced by a jet of air directed at the capsule to therebyrelease the capsule into the longitudinally extending recess.

Alternative capsule inserter wheels could also be used and analternative capsule inserter wheel configuration will now be described.The capsule inserter wheel has radially extending cylindrical recessesspaced equidistantly around its cylindrical surface. The base of eachrecess is formed by the free end of a plunger or piston. Each piston isresiliently biased by a spring radially towards the centre of the wheel,but is movable radially outwards against this spring bias to sweepthrough the recess and so positively eject its contents. Sequentialoperation of the pistons or plungers as the wheel rotates clockwise iseffected by means of stationary cam surface which engages with theradially inner end of the pistons or plungers over a portion of theirtravel path.

As the inserter wheel rotates, each recess is filled with an individualfrangible capsule from a hopper as the recesses pass around the top oftheir travel path. The pistons or plungers are operated by a cam surfaceto empty the capsules from the inserter wheel recesses, into thelongitudinally extending recess of the advancing rod of partiallygathered filtering material, at the bottom of the travel path of therecesses.

The aperture in the gathering shoe 122 enables the capsule inserterwheel to extend into the gathering shoe 122 and thereby insert one ormore capsule into the recess within the rod of partially gatheredfiltering material. The rotational speed of the capsule inserter 130 andthe longitudinal speed of the advancing rod of partially gatheredfiltering material is constant so the capsules are inserted into the rodof partially gathered filtering material at regular intervals and so arepositioned at regular intervals within the core of filtering material.The presence of a recess in the partially gathered rod of filteringmaterial aids the placement of the one of more capsules and improves thecapsule positioning within the finished filter element.

Following capsule insertion, the partially gathered rod continues toadvance longitudinally and is further gathered by the walls of thegathering shoe. As the internal diameter of the gathering shoedecreases, the partially gathered rod is further gathered and condensedsuch that the recess is closed and a longitudinally advancing rodcomprising a longitudinally extending core of filtering material and oneor more capsules is provided.

Further processing steps are carried out on the rod as described abovewith reference to FIG. 1 .

FIG. 8 shows an apparatus for separating and gathering two or moresheets of filtering material. The apparatus includes the same structureand components as described above with reference to FIGS. 2 to 4 , butthe apparatus does not include a capsule inserter.

FIG. 5 shows a side view of the cone 110. As shown in FIG. 5 , the conehas a first end 112 which has a larger diameter than the second end 114.A first section of the cone extending from the first end 112 of the conehas a constant diameter. A second section of the cone extends from thefirst section and has a diameter that decreases from the first end ofthe second section to the second end of the second section, such thatthe second section is tapered. A final third section extends from thesecond end of the second section and includes a narrower and constantdiameter.

FIG. 6 is a perspective view of a filter element according to theinvention.

The filter element 200 shown in FIG. 6 comprises a longitudinallyextending core of filtering material 202 formed from two sheets of paperfiltering material having a basis weight of 36 g/m², a thickness of 85μm and each sheet having a width of 110 mm. The core 202 comprises acapsule 204 positioned centrally within the core. The capsule is afrangible capsule containing 2.5 g of menthol in an oil carrier. Thecapsule has a diameter 3.35 mm. The filter element 200 also includes apaper plug wrap 206 which surrounds the core and is secured by a lappedand stuck seam as is known in the art. The filter element has acircumference of 24 mm and a length of 27 mm.

FIG. 6 shows a perspective sectional view of the filter element 200shown in FIG. 5 . FIG. 6 illustrates the structure of the capsule 204which includes a capsule shell 208 comprising gelatine, and a liquidmenthol flavourant solution 210 within the capsule shell. It will beappreciated that other flavourants may be contained in the capsule 204.

The filter element shown in FIGS. 5 and 6 may be made according to themethod described above with reference to FIGS. 1 to 4 .

The filter element 200 shown in FIGS. 5 and 6 may be joined to a wrappedtobacco rod (not shown) to form a filtered smoking article, such as afiltered cigarette. The filter element 200 may be joined to the wrappedtobacco rod by ring tipping paper, in which the tipping paper engagesaround only the adjacent ends of the filter element and wrapped tobaccorod to thereby leave some of the plug wrap 206 exposed. Alternatively,the filter may joined by a full tipping overwrap which engages aroundthe entire length of the filter element and the adjacent end of thewrapped tobacco rod.

1-33. (canceled)
 34. A method for making a filter element comprising thesteps of: advancing two or more sheets of filtering material in alongitudinal direction; separating the two or more sheets oflongitudinally advancing filtering material; gathering the separatedsheets of longitudinally advancing filtering material to form apartially gathered rod of filtering material having a longitudinallyextending recess; inserting an additive release vessel into thelongitudinally extending recess; gathering the filtering material aroundthe additive release vessel to close the recess and thereby form a rodcomprising a longitudinally extending core of filtering material and oneor more additive release vessels.
 35. The method according to claim 34,wherein the two or more sheets of longitudinally advancing filteringmaterial are separated by a separator; and/or wherein the gathering ofthe separated two or more sheets of longitudinally advancing filteringmaterial comprises drawing the separated two or more sheets oflongitudinally advancing filtering material into a gathering chamber.36. The method according to claim 35, wherein the separator is coupledto the gathering chamber such that the two or more sheets oflongitudinally advancing filtering material are separated beforeentering the gathering chamber, and the separator prevents completegathering of the two or more sheets of longitudinally advancingfiltering material to thereby form a longitudinally extending recess inthe partially gathered filtering material.
 37. The method according toclaim 35, wherein the gathering chamber comprises an inlet for receivingthe separated sheets of filtering material and an outlet for thepartially gathered filtering material to exit, and wherein the gatheringchamber is tapered longitudinally away from the inlet; and/or whereinthe separator is longitudinally tapered and/or extends into and along atleast part of the length of the gathering chamber; and/or wherein theseparator is tapered in the same direction as the gathering chamber. 38.The method according to claim 36, wherein the separated two or morelongitudinally advancing sheets of filtering material are drawn into apreliminary chamber before entering the gathering chamber; for examplewherein the preliminary chamber comprises an inlet and an outlet,wherein the outlet of the preliminary chamber is joined to the inlet ofthe gathering chamber, and wherein the separator extends into and alongat least part of the length of the preliminary chamber.
 39. The methodaccording to claim 34, wherein the additive release vessel is insertedinto the longitudinally extending recess by an additive release vesselinserter; for example wherein the additive release vessel insertercomprises a rotating drum or wheel.
 40. The method according to claim34, wherein the two or more sheets of filtering material are embossed;and/or wherein the filtering material comprises a non-woven material;and/or wherein the filtering material comprises paper; and/or whereinthe two or more sheets of longitudinally advancing filtering materialcomprise 2, 3 or 4 sheets of longitudinally advancing filteringmaterial.
 41. The method according to claim 34, comprising a step ofcutting the rod to form a filter element comprising a longitudinallyextending core of filtering material and one or more additive releasevessels.
 42. A filter element comprising a longitudinally extending coreof filtering material and an additive release vessel enclosed within thelongitudinally extending core of filtering material; wherein thelongitudinally extending core of filtering material is formed from twoor more sheets of filtering material.
 43. The filter element accordingto claim 42, wherein the filtering material comprises paper or anon-woven material; and/or wherein the additive release vessel is acapsule.
 44. An apparatus for making a filter element comprising: aseparator for separating two or more longitudinally advancing sheets offiltering material; a gathering chamber configured to gather theseparated longitudinally advancing sheets of filtering material and forma rod of partially gathered filtering material; wherein the separator iscoupled to the gathering chamber such that the separator and thegathering chamber are configured to form a longitudinally extendingrecess in the rod of partially gathered filtering material; and aninserter configured to insert one or more additive release vessels intothe longitudinally extending recess.
 45. The apparatus according toclaim 44, wherein the gathering chamber comprises an inlet for receivingthe separated sheets of filtering material and an outlet for thepartially gathered filtering material to exit, and wherein the gatheringchamber tapers longitudinally away from the inlet; and/or wherein theseparator is longitudinally tapered and extends into and along at leastpart of the length of the gathering chamber; for example wherein theseparator is tapered in the same direction as the gathering chamber. 46.The apparatus according to claim 44 comprising: a preliminary chambercomprising: an inlet and an outlet; wherein the outlet of thepreliminary chamber is joined to the inlet of the gathering chamber; andwherein the separator extends into and along part of the length of thepreliminary chamber; for example wherein the preliminary chamber taperslongitudinally away from the inlet.
 47. The apparatus according to claim44, wherein the gathering chamber comprises a longitudinally extendingaperture for receiving the inserter; and/or wherein the gatheringchamber is configured to gather the filtering material around theadditive release vessel to close the recess and thereby form acontinuous rod comprising a longitudinally extending core of filteringmaterial and one or more additive release vessels; and/or wherein theapparatus comprises a rod cutter configured to cut a rod comprising alongitudinally extending core of filtering material and one or moreadditive release vessels to form a filter element; and or wherein theinserter comprises a rotating drum or wheel configured to insert the oreach additive release vessel into the longitudinally extending recess.48. An apparatus for separating and gathering two or more sheets offiltering material, the apparatus comprising: a gathering chambercomprising an inlet and an outlet, wherein the inlet has a largerdiameter than the outlet such that the gathering chamber islongitudinally tapered; a separator extending at least part of the wayinto the gathering chamber and protruding from the inlet of thegathering chamber; wherein the separator and the gathering chamber areconfigured to separate and partially gather two or more sheets offiltering material to thereby form a partially gathered longitudinallyextending rod of filtering material comprising a longitudinallyextending recess.